Improvement in mariners compasses



` 1. L G. H. Buss. Compass.

f Patented May 24, 1870.1

III/miam posed.

waited gieten 'stent Alilihzc.

Letters Patent No. 103,286, dated May 24, 1870.

IMPROVEMENT 1N MARINeas coMPAsses.

The Schedule referred to in these Letters Patentand making part of thesame.

To all lvhom it may concern `Be it known that we, JOHN BLIss and GEORGEH. Buss, oi Brooklyn, in the county of Kings and State of New York, haveinvented and made a new and-useful Improvement in Liquid Compasses; andwe do hereby declare the following to be a full, clear, and exactdescription of the said invention, reference being had to the' annexeddrawing making part ofthis specication, wherein we have represented thesaid com-v pass by a vertical section of the same.

Liquid Compasses have, heretofore, been made, in which the case was lledwith ralcohol or other liquid, so as to partially `float the card andneedle, and the expansion of the liquid under varying temperatures hasbeen allowed for by a portion. of the case, or a chamber connectedthereto, being of thin sheet metal, and, in some instances, anair-chamber has-been pro- When the metal is moved by the expandingliquid the case cannot be made of thick metal, and the thin metal isliable to injury.

There au air-chamber has been used there was a liability for" bubbles ofair to escape from the expansion air-chamber into 4the compass-case, orelse the compass has been" rendered inconvenient or unsightly inconsequence of the air-chamber being above the compass-ease, and thischamber obstructed l(he view ofr the cornpass-card.`

Our invention relates tovan air-chamber combined with the liquid-chamberof Vthe compass-case, the two being connected together by small openingsor pores in the liquid portions of the chamber, in such a manner thatonly theliquid canpass from -one chamber to the other, in consequencevof expansion or contraction under varying temperature, and the air willbe confined eiectually, but act as an elast-ie cushion.

In the drawing-'" a. is the bowlof the compass, formed of sheet metalspun up to shape, instead of being cast as heretofore, soas to belighter and of `more dense and reliable metal, and not liable to leak.

The ring b is soldered or brazed to the upper edge of the 'bowl a, andreceives the glass c, rubber or elastic packing d, and clamping-ring e,pressed down by screws.

f'lhe diaphragm f is introduced within the bowl a,- so that the'spaeefor the liquid and compass-card will be lessened, but the swing of 'diecard `will not bo interfered with.

Below the'diaphragm j' is the expansion vessel g, that is tov be filledwith liquid to about the height shown previously, to introduce the tubeh, thatis secured firmly to its scat upon 1", so as to be air-tight.

The lower end-of this tube h terminates near the center of the chamberor vessel y, so that it will always remain in the liquid, even if thecompass is turned on its side, or inverted so that air will not enter zthis tube. A As an additional precaution we make use of a screwcap, t,with a very small hole, that is sufficient for the liquid to passgradually from one vessel to the other. The end of this cap c' isrounding, so that bubbles ofV air cannot lodge, even if the compass isshaken.

`Furtherrnore, we introduce porous material where the liquid passes fromone chamber `to the other.

-lVe find that sponge introduced in the tube 7i., a l

piece of porous stone or packing of fibrous material, or-other likesubstance, applied between the said chambers,l will allow the liquid `topass, but, being saturated with liquid, will not allow v`air to pass.

Small spring valves, opening inopposite directions when employed, arethc equivalent of the `porous Inriterial. l

'lhc porous materials or valves allow of the airexpansion chamber beinglocated in some other part of the compass-bowl than the bottom thereof,suchy vas in the sides of the bowl or in the compass-card.

lhe'tube h is extended up, toform the pivot l.: for

the compass-card. The openings, 3, through the base oi' said pivot,communicate with thetube h.. The compass card is formed of' a sheetmetal annulus, l, coated with vitrifed enamel. The necessary points andletters are formed and burnt in by vitrifying the cnamelina mannersimilar to that adopted in the manufact-ureof watch and'cloekaces.

This mode of making the compass-card insures great accuracy and beauty,and prevents injury to the -compass-case, either as to the color or theaccuracy o i' the divisions, by the action of the liquid.

The annular' compass-card l is supported by the float nl, of cork orother wooden material, formed with a flange, 4, for the card to restupon.

. v The magnetic needle n is provided with the conical socket for thepivot, as usual; said conical socket is shown as entering the cork-floatm., and being retained by a nut, 5.

, i This cork or wood float projecting through the annular compass-cardcauses the weight to be partially floated, so that it does not rest soheavily on the pivot k, and there is no tendency to tip or incline thecard," as there would be it' the floating power was entirely below thecompass-card.-

A thin sheet-metal cap, Vo, may be placed over the float m, to renderthe appearancemore acceptable.

In order to prevent the cork or wood absorbing the liquid and lesseningits buoyancy, we employ a coatl ing of collodion, mixed with :t pigment,such as zincwhite, and the same can he employed for painting the insideof' the bowl.

Alcohol does not affect said collodion, hence it is admirably adapted tothis object. Y

Vhat we claim, and desire to securel by Letters Patent, is

1. A liquid compass, formed with two spaces, one for the compass-card,the other containing liquid and air, when the two are connected by a.tube or opening provided with porous material, or its equivalent, forpreventing air passing into the compass-space, substantia-lly es setforth.

2. The chamber g, below the coinpass-chamber, in combination with thetube h, the opening of which is .located at or neer the center of -thevessel y, as and for the purposes specified.

In witness whereof we have hereunto lset our signatures this 3d day ofMay, A. D. 1869.

JOHN BLTSS. GEO. H. BLISS.

Witnesses GEO. D. WALKER, GEo. T. PINCKNEY.

